1. Capacity: how many watt-hours?
Capacity is the size of the tank. Add up what you want to run: each device's running watts multiplied by the hours you will use it. Then divide by about 0.85, because converting battery power to AC loses some energy along the way.
Capacity needed (Wh) = Σ (watts × hours) ÷ 0.85Example: a 60 W laptop for 5 hours plus a 10 W phone charger for 3 hours is 300 + 30 = 330 Wh. Divided by 0.85, you want roughly 390 Wh, so a 400–500 Wh station gives a little margin. The calculator does this for any list of devices.
2. Output: how many watts at once?
Output is the size of the pipe. Add the running watts of everything you will use at the same time, then add headroom. Our calculator suggests 25% as a sensible default.
Also look for the surge (peak) rating. Refrigerators, pumps and power tools draw a short burst when a motor or compressor starts, often well above their running watts. A station that can handle the surge but not the running load is fine for a moment and then trips, and the reverse is also true, so check both numbers.
Heat is expensive. Kettles, space heaters, hair dryers and electric cooking elements pull from roughly 1,000 W upward. If you need those, you are shopping in the large-station category, and even then runtimes are short.
3. Battery chemistry: LiFePO4 vs lithium-ion
This is the biggest difference between models that otherwise look alike on paper. Typical manufacturer-quoted ranges:
| LiFePO4 (LFP) | Lithium-ion (NMC) | |
|---|---|---|
| Rated charge cycles | about 2,000–5,000 | about 500–1,500 |
| Weight for same capacity | Heavier | Lighter |
| Thermal stability | Generally better | Good with a quality BMS |
| Best for | Home backup, frequent use, long-term value | Backpacking, travel, occasional use |
If you will cycle the battery often, for example daily solar charging or regular outage backup, LFP's longer rated life usually wins on cost over time even if it weighs more. If you carry the unit a lot and use it a few times a year, a lighter NMC model can make more sense. Cycle ratings are claims made under test conditions, so the warranty length is the more useful signal of how much the maker trusts them.
4. Solar input: the spec people skip
If you plan to recharge with panels, three numbers matter: the maximum solar input in watts (more panels than this add nothing), the accepted voltage range (your panel setup must fall inside it), and the connector type. A 2,000 Wh station with only a 200 W input takes a long time to fill from the sun even with a big array. Our solar charging guide walks through the math.
5. Ports, UPS mode and extras
- Port mix. Count what you will actually plug in: AC sockets, USB-C with enough watts for a laptop, USB-A, a 12 V car socket.
- Pass-through / UPS mode. Lets the station sit between the wall and your gear and switch to battery in an outage. Useful for routers and computers; check the switchover time.
- Expandability. Some models accept extra battery modules later, which spreads the cost.
- Noise and fans. Matters in a bedroom, less so in a camp.
6. Compare value fairly
Cost per Wh = price ÷ capacity (Wh)Use this to compare like with like, then adjust for chemistry, output, solar input and warranty. A cheaper-per-Wh station with a 200 W solar cap may cost you more in practice than a pricier one you can recharge in a day. Weight, warranty length and support also belong in the decision.
Quick answers
How big a power station for a weekend camping trip?
A phone, a few LED lights and a small fridge are often well served by 500–1,000 Wh. Run your own numbers in the calculator, because a powered cooler or a laptop changes the answer quickly.
Is it worth getting a bigger one than I need?
A little headroom is wise because batteries are not 100% usable and loads add up. Much bigger than you need means paying for weight and capacity you will rarely use, so size to your plan plus a margin.
Can I use a power station as a home battery?
It can back up selected devices, and with pass-through some models act like a small UPS. It is not a replacement for a whole-home battery system, which is a different product category.